(1) Field of the Invention This invention relates generally to a collapsible tube used to contain and dispense fluids, and particularly to a seal on the dispensing orifice of such a tube.
(2) The Prior Art Collapsible tubes are packages in tube form having a dispensing orifice at one end of a deformable tube. The tube is deformed and collapsed by squeezing so that the contents are forced out of the orifice. Such tubes are used to contain toothpaste, pharmaceuticals, cosmetics, personal care products, artists' pigments, adhesives, sealants and caulking materials, greases and lubricants, foods and condiments, and many other products. A collapsible tube generally has a screw closure cap.
Such tubes are made of metal, such as lead, tin and aluminum, or of plastic or laminate materials.
Collapsible tubes often have a seal across the dispensing orifice of the tube, particularly when used for medicinal products. The seal prevents the tube contents from leaking out prior to use. Also, the seal prevents any atmospheric contact with the tube contents, since the tube is sealed in an air-tight manner.
In use, the seal is pierced by, for instance, a point formed in the tube screw cap.
A method of forming a seal on a collapsible tube is shown in U.S. Pat. No. 4,938,818, incorporated herein by reference.
This invention is specifically directed to a method of testing such a seal for leaks.